Removing duplicate lines from a text file

This script is co-authored in part by Russel with Jersey Post:

https://community.cdata.com/members/russell-jerseypost-190

The following code will enumerate the lines of a multiline file, such as a txt or csv, and output a new file with only the unique lines returned:

<arc:set attr="file.file" value="[FilePath]" />

<arc:call op="fileReadLine" item="file">
  <!-- enumerate the file and add the rows to a collection -->
  <arc:check attr="newrows.[file.file:data|md5hash(false)]">
    <arc:else>
      <arc:set item="newrows" attr="[file.file:data|md5hash(false)]" value="[file.file:data]" />
      <arc:set attr="tmp.keys#" value="[file.file:data|md5hash(false)]" />
    </arc:else>
  </arc:check>
</arc:call>

<!-- repopulate the row data --> 
<arc:set attr="output.data">
  <arc:enum attr="tmp.keys">[newrows.[_value]]\n</arc:enum>
</arc:set>

<arc:push item="output" />